8.1 and Allison transmission - The 1947 - Present Chevrolet & GMC Truck Message Board Network

68Green · 12-17-2017, 12:30 AM

Was wanting to do a 6.0 and 4l80 transmission swap in my 68 c10, but found a donor truck with an 8.1 and Allison transmission for a pretty good deal. I'm not sure which way to go so looking for opinions

57taskforce · 12-17-2017, 02:05 AM

As far as gas motors go the 8.1 is hard to beat if your not worried about gas mileage. They make something like 375 lbft of torque at idle. I’ve got one in my wife’s suburban and even with 240,000 it still hauls the mail. It gets 9-10 mpg on average. I have a heavy foot though.

**LockDoc** · 12-17-2017, 02:08 PM

-
Not sure on the 6.0 but here is some info on the 8.1 - 496ci.

http://67-72chevytrucks.com/vboard/s...d.php?t=374432

If you type "8.1 engine" into the google search box above (minus the quotes) and click on the circle in front of 67-72chevytrucks.com, then click on the "Google" button you will find a lot of info on the subject.....

LockDoc

**davischevy** · 12-17-2017, 03:05 PM

We ran an 8.1 and Allison 300,000 miles with no problems.

That thing would pull a stump.

10 MPG no matter how long you held your breath.

12-17-2017, 12:30 AM	#1
68Green Registered User Join Date: Dec 2017 Location: Texas Posts: 2	8.1 and Allison transmission Was wanting to do a 6.0 and 4l80 transmission swap in my 68 c10, but found a donor truck with an 8.1 and Allison transmission for a pretty good deal. I'm not sure which way to go so looking for opinions

12-17-2017, 02:05 AM	#2
57taskforce All about them K’s Join Date: Jun 2014 Location: Land of Entrapment Posts: 6,487	Re: 8.1 and Allison transmission As far as gas motors go the 8.1 is hard to beat if your not worried about gas mileage. They make something like 375 lbft of torque at idle. I’ve got one in my wife’s suburban and even with 240,000 it still hauls the mail. It gets 9-10 mpg on average. I have a heavy foot though. __________________ Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne: 5” lift, 35’s, front dana 60 blah blah blah… http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB: 4” lift 33”s… in a million pieces http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 35x12.5x20’s

12-17-2017, 02:08 PM	#3
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,771	Re: 8.1 and Allison transmission - Not sure on the 6.0 but here is some info on the 8.1 - 496ci. http://67-72chevytrucks.com/vboard/s...d.php?t=374432 If you type "8.1 engine" into the google search box above (minus the quotes) and click on the circle in front of 67-72chevytrucks.com, then click on the "Google" button you will find a lot of info on the subject..... LockDoc __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 -

12-17-2017, 03:05 PM	#4
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,860	Re: 8.1 and Allison transmission We ran an 8.1 and Allison 300,000 miles with no problems. That thing would pull a stump. 10 MPG no matter how long you held your breath. __________________ other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.